Possible toxicity of chronic carbon dioxide exposure associated with face mask use, particularly in pregnant women, children and adolescents – A scoping review

"Abstract

Introduction: During the SARS-CoV-2-pandemic, face masks have become one of the most important ubiquitous factors affecting human breathing. It increases the resistance and dead space volume leading to a re-breathing of CO2. So far, this phenomenon and possible implications on early life has not been evaluated in depth.

Method: As part of a scoping review, literature was systematically reviewed regarding CO2 exposure and facemask use.

Results: Fresh air has around 0.04% CO2, while wearing masks more than 5 min bears a possible chronic exposure to carbon dioxide of 1.41% to 3.2% of the inhaled air. Although the buildup is usually within the short-term exposure limits, long-term exceedances and consequences must be considered due to experimental data. US Navy toxicity experts set the exposure limits for submarines carrying a female crew to 0.8% CO2 based on animal studies which indicated an increased risk for stillbirths. Additionally, mammals who were chronically exposed to 0.3% CO2 the experimental data demonstrate a teratogenicity with irreversible neuron damage in the offspring, reduced spatial learning caused by brainstem neuron apoptosis and reduced circulating levels of the insulin-like growth factor-1. With significant impact on three readout parameters (morphological, functional, marker) this chronic 0.3% CO2 exposure has to be defined as being toxic. Additional data exists on the exposure of chronic 0.3% CO2 in adolescent mammals causing neuron destruction, which includes less activity, increased anxiety and impaired learning and memory. There is also data indicating testicular toxicity in adolescents at CO2 inhalation concentrations above 0.5%.

Discussion: There is a possible negative impact risk by imposing extended mask mandates especially for vulnerable subgroups. Circumstantial evidence exists that extended mask use may be related to current observations of stillbirths and to reduced verbal motor and overall cognitive performance in children born during the pandemic. A need exists to reconsider mask mandates...

1. Introduction

... Government data from the end of the year 2021 show that an estimated 4 496 149 755 people worldwide (58% of world population) have been confronted with a mask obligation...

3.1 Effects of masks on carbon dioxide re-breathing

In the study of Ulrike Butz's dissertation (an internally peer reviewed thesis research study) focusing on possible rebreathing of carbon dioxide in 15 healthy adult male volunteers, a carbon dioxide partial pressure of up to 21–24 mmHg was found under a surgical mask after 30 min. This corresponds to about 2.8–3.2% carbon dioxide of the inhaled air under the mask...

6. Conclusions

A significant rise in carbon dioxide occurring while wearing a mask is scientifically proven in many studies, especially for N95-masks (Table 2) due to their higher deadspace and breathing resistance. Fresh air has around 0.04% CO2 while masks bear a possible chronic exposure to low level carbon dioxide of 1.41–3.2% CO₂ of the inhaled air in reliable human experiments. Animal experimental data shows deleterious proven effects of elevated CO₂ of inhaled air in the long term with threshold values of above 0.3%, 0.5% and 0.8% (Neuron destruction, impaired memory and learning, increased anxiety, destruction of cells in testes, stillbirth, and birth defects). The risk for children's mental development starts at levels of above 0.3%, to adolescent male sexual development at levels of above 0.5%, as well as to unborn life at levels of above 0.8% resulting in reduced cognitive performance, reduced fertility and stillbirths (Table 3).

There is circumstantial evidence that popular mask use may be related to current observations of a significant rise of 28% to 33% in stillbirths worldwide and a reduced verbal, motor, and overall cognitive performance of two full standard deviations in scores in children born during the pandemic."